textproduct: Rapid City

KEY MESSAGES

- Light snow over much of western SD and portions of northeastern WY today and Friday. 6 to 9" with locally higher amounts over portions of the northern Black Hills and Bear Lodge mountains. Accumulations of less than 3" expected over the plains.

- Another round of light precip moves through the area Saturday with snow changing over to rain as warm air moves into the region.

- Above average temperatures and mostly dry weather returns Sunday into early next week

DISCUSSION

(Today Through Wednesday) Issued at 156 AM MST Thu Jan 29 2026

Current upper air analysis depicts upper level low centered over Ontario with ridge axis over the PNW. The Northern Plains sits under northwest flow with lead shortwave over NE. Water vapor imagery depicts weak upper wave over western SD and eastern MT with moisture streaming into the region. Current sfc analysis shows a stalled frontal boundary draped over far western SD. Light snow has developed along this boundary and is falling across the western SD plains and the northern Black Hills.

Unsettled northwest flow will continue over the region today with stalled out frontal boundary and baroclinic zone remaining over western SD. Continued moisture transport into the region along with weak forcing associated with waves embedded in the northwest flow will support a prolonged period of light snowfall over northwestern into south central SD and the northern Black Hills. Froude numbers of 1 to 1.5 and 0-2km RH of 90-100% will support upslope enhanced snow across much of the northern Black Hills. The most recent model runs have bumped up QPF and thus snow totals over the northern Black Hills and Bear Lodge Mountains (29/00z HREF grand ensemble run has 60-80% probs of storm total QPF exceeding 0.5" over the northern Black hills). Accumulations of 6 to 9" are now likely over the higher elevations of the northern Black Hills and Bear Lodge Mountains with locally higher accumulations of 10 to 12" possible. While this does put us at the threshold for a Winter Storm Warning, given the long duration of this event (around 36-48 hours) and the limited coverage of warning criteria accumulations, will hold off on upgrading the Winter Weather Advisory already in place.

Weak upper ridging will provide a short break from precip Friday evening before quick moving upper shortwave and sfc warm front sweep through the area Saturday. So far expecting a band of light precip to cross the region Saturday morning into the afternoon. Precip will start off as snow Saturday morning before changing over to rain as warm air moves in. Forecast soundings indicate that a brief period of freezing rain is possible across northwestern SD Saturday afternoon though not anticipating any ice accumulations.

Upper ridge pushes into the region by Sunday with above average temperatures and mostly dry weather expected through Monday. Weak shortwave progged to slide through the region Tuesday with additional chances for light precip, mainly over the Black Hills and portions of western SD. Temperatures through the mid week expected to remain slightly above seasonal averages.

AVIATION

(For the 06Z TAFS Through 06Z Thursday Night) Issued At 1007 PM MST Wed Jan 28 2026

Light snow has developed across portions of western South Dakota this evening with transient MVFR/IFR conditions. MVFR/IFR conditions in low clouds and snow will persist through the forecast period across the region. Have implemented MVFR/IFR conditions by 10Z Thursday at GCC and 11Z at RAP. Confidence in low cigs and vis is higher at RAP where occasional IFR visibility is expected with the heavier snow showers. Lowest flight conditions expected across northern Black Hills and northwestern South Dakota with IFR/LIFR conditions likely.

UNR WATCHES/WARNINGS/ADVISORIES

SD...Winter Weather Advisory from 5 AM early this morning to 5 PM MST Friday for SDZ024. WY...Winter Weather Advisory from 5 AM early this morning to 5 PM MST Friday for WYZ057.